Apparatus for determining the concentration of an oil-water mixture



W. L. ROBERTS APPARATUS FOR DETERMINING THE CONCENTRATION Oct. 20, 196 4I OF AN OIL-WATER MIXTURE Filed Oct. 25, 1962 mhattem INVEN TOR. W/LLIAM L. ROBE T5 Attorney United States Patent This invention relates toapparatus for determining the concentration of an oil-water mixture andmore particularly to determining the oil-water ratio of lubricants usedin the operation of a cold rolling mill and maintaining a predeterminedoil-water ratio. In the operation of a cold rolling mill, particularly astrip mill, an oil-water mixture is sprayed on the strip. The oil-watermixture is recirculated and since varying amounts of oil and water aredepleted by evaporation and drag-out it is impossible to determine theproper addition of each that must be made to maintain the desiredpredetermined concentration. For'satisfactory operation it is necessaryto maintain such a predetermined concentration. At present a sample ofthe lubricant is periodically withdrawn and allowed to stand for aperiod sufiicient to allow the water and oil to separate. The respectiveamounts of the water and oil are then determined and the proper amountof either oil or water is added to the lubricating system. This is timeconsuming and unsatisfactory be- I cause the operator may forget ordelay in making the determination. Thus, the mill may operate for someperiod of time without a proper'lubricant.

It is therefore an object of my invention to provide a system thatautomatically determines the oil-water ratio of the lubricant in a coldrolling mill.

Another object is to provide such apparatus that also automaticallymaintains a desired concentration of oil in the oil-Water mixture.

These and other objects will be more apparent after referring to thefollowing specification and attached drawings, in which:

The single figure is a schematic view of a rolling mill lubricatingsystem incorporating my invention therein.

Referring more particularly to the drawing reference numeral 2 indicatesthe work rolls of a cold rolling mill. The usual back-up rolls 4 areprovided for the work rolls 2. The strip S passes through the work rolls2 in the direction of the arrow. Manifolds 6 and 8 are provided aboveand below the strip pass line so as to deliver sprays 10 and 12 oflubricant to the surface of the strip. The lubricant not carried away bythe strip or evaporated into the atmosphere falls into a sump 14. Arecycle line including conduit 16, reservoir 18, pump 20 and conduit 22returns the lubricant to the manifolds 6 and 8. The apparatus so fardescribed is conventional.

According to my invention I provide a branch line 24 connected to theconduit 22 and provided with a pump 26. The branch line 24 leads to acentrifuge 28 which may be of any standard type. The AS-16 SuperCentrifuge manufactured by The Sharples Corporation, 2300 WestrnorelandStreet, Philadelphia 40, Pennsylvania is preferred. The oil passes fromthe centrifuge 28 through a branch conduit 38 back to the main conduit22. A

flow meter 32 is provided in the branch conduit 30. The separated waterpasses through a branch conduit 34 back to the main conduit 22. A flowmeter 36 is provided in the conduit 34. The flow meters 32 and 36 areidentical and are preferably of the type manufactured by The FoxboroCompany, Foxboro, Massachusetts and shown and described by Figure 10672on page 23 of their Bulletin 427-1. The flow meters 32 and 36 provide aDC. po

tential proportional to the flow rate therethrough. The

voltage from flow meter 36 is applied across a potentiom eter 38 and theslider 388 of the potentiometer selects a "ice percentage of the voltage36 and applies it to an amplifier 40 which compares this voltage withthe voltage applied by the flow meter 32. If a difference is detected itis amplified and applied to a balancing motor 42 in such a direction asto move the slider 385 until the voltages are equal. The position of theslider 388 represents the ratio of the two voltages and hence the ratioof the oil and water. A scale 44 calibrated to indicate oilconcentration is provided with a pointer 44? which is mechanicallyconnected to motor 42. Other types of ratio indicating devices may beused in place of that shown.

In operation, a sample of lubricant is continuously withdrawn from theconduit 22 by means of the pump 26 and caused to flow through centrifuge28 and the meters 32 and 36 will operate to provide signals proportionalto oil and Water flow respectively. These signals are compared and theratio indicated by pointer 44? on scale 44. When this ratio departs fromthat desired the operator will add the required amount of oil or waterto the system.

Addition of the oil and water may be done automatically instead ofmanually. Water may be delivered through a conduit 46 having a floatcontrolled valve 48 therein so as to maintain a predetermined level ofliquid in the reservoir 18. Oil may be delivered into the reservoir 18through a conduit 58 having a solenoid operated valve 52 therein. Themotor 42 is connected to slider arm 543 of a linear potentiometer 54 anda positive potential 56 is applied across the potentiometer 54.Potential 58 between slider 54S and ground will be proportional to theoil-water ratio and this voltage is applied to a relay coil 60 through arectifier 62 and potentiometer 64. A battery 66 is mounted in parallelwith potentiometer 64. Relay 60 has a normally open contact 686 which isconnected in series with a motor 68 to an AC. power source L1, L2. Themotor 68 rotates a cam 70 having a low point 72 therein. The cam '70operates a switch 74 having normally open contacts 740 and 74C1.Contacts 74C are mounted in parallel with contact 60C so as to provide aholding circuit for motor 68. Contact MCI is connected in series withsolenoid 52S and battery 76.

In automatic operation, the float valve 48 will maintain the desiredlevel of liquid in the reservoir 18 by permitting flow of water to thereservoir through conduit 46 when the liquid falls below a predeterminedlevel. Under these circumstances the oil concentration will graduallyreduce and when it reaches a level below that desired the voltage 58between slider arm 54S and ground will fall below a certain valuecorresponding to that set up on potentiometer 64 and the relay 66 willbe actuated through conduction of rectifier 62. This causes contact 60Cto close, thus starting motor 68 in operation. As motor 68 startsrotating the cam 70 will rotate from the position shown to closecontacts 740 and 74C1. Clos ing of contact 74C completes the holdingcircuit to motor 68 and causes it to complete one revolution. In themeantime relay 60 will be deenergized. When the motor 68 completes onerevolution the cam 7t) will have returned to its original position sothat the contacts of switch 74 will be open. Closing of contact 7401energizes solenoid 528, thus holding valve 52 open while the motor 68completes one revolution. This will permit a predetermined amount of oilto flow at a slow rate into the reservoir 18. If the voltage 58 remainsbelow that set up on potentiometer 64 after the ,oil addition. the relay60 will again be energized and another slug of oil will pass into thereservoir 18.

While one embodiment of my invention has'been shown and described itwill be apparent that other adaptations and modifications may be madewithout departing from the scope of the following-claims. For example;other timing mechanism may be substituted for motor 68 and associatedmechanism.

I claim:

1. In a rolling mill having means for spraying an oil- Water mixture toa workpiece passing through the mill, a recycle line including areservoir for receiving oil-Water mixture from said spray means, and amain conduit for conveying oil-water mixture from said reservoir to saidspray means, the combination comprising a branch line from said recycleline for obtaining a sample of said oilwater mixture, a centrifuge insaid branch line for separating said mixture into oil and watercomponents, a first branch conduit for receiving said separated oil andreturning it to said main conduit, a first flow meter in said firstbranch conduit, a second branch conduit for receiving said separatedWater and returning it to said main conduit, a second flow meter in saidsecond branch conduit, and means for comparing the flow through saidfirst and second flow meters to obtain a signal proportional to theconcentration of the oil in said oil-water mixture.

2. In the combination of claim 1 means operable by said signal tocontrol flow of oil to said reservoir to obtain the desiredconcentration of oil in said oil-water mixture.

3. In a rolling mill having means for spraying an oil- Water mixture toa workpiece passing through the mill, a recycle line including areservoir for receiving oil-water mixture from said spray means, and amain conduit for conveying oil-water mixture from said reservoir to saidspray means, the combination comprising a branch line from said recycleline for obtaining a sample of said oilwater mixture, a centrifuge insaid branch line for separating said mixture into oil and watercomponents, a first branch conduit for receiving said separated oil andreturning it to said main conduit, a first flow meter in said firstbranch conduit, a second branch conduit for receiving said separatedwater and returning it to said main conduit, a second flow meter in saidsecond branch conduit, means for comparing the flow through said firstand second flow meters to obtain a signal proportional to theconcentration of the oil in said oil-water mixture, means for deliveringWater to said reservoir to maintain a desired liquid level therein,means for delivering oil to said reservoir, and means operable by saidsignal to permit flow of oil to said reservoir to obtain the desiredconcentration of oil in said oil-Water mixture.

4. In a rolling mill having means for spraying an oilwater mixture on aworkpiece passing through the mill, a recycle line including a reservoirfor receiving oil-water mixture from said spray means, and a mainconduit for conveying oil-water mixture from said reservoir to saidspray means, the combination comprising a branch line from said recycleline for obtaining a sample of said oil-water mixture, means forseparating said mixture sample into oil and water components, a firstbranch conduit for receiving said separated oil, a first flow meter insaid first branch conduit, a second branch conduit for receiving saidseparated water, a second flow meter in said second branch conduit,means for comparing the flow through said first and second flow metersto obtain a signal proportional to the concentration of the oil in saidoil-water mixture, and means operable by said signal to control fiow ofoil to said reservoir to obtain the desired concentration of oil in saidoil-water mixture.

Mallory Apr. 11, 1939 Denney June 24, 1941

4. IN A ROLLING MILL HAVING MEANS FOR SPRAYING AN OILWATER MIXTURE ON A WORKPIECE PASSING THROUGH THE MILL, A RECYCLE LINE INCLUDING A RESERVOIR FOR RECEIVING OIL-WATER MIXTURE FROM SAID SPRAY MEANS, AND A MAIN CONDUIT FOR CONVEYING OIL-WATER MIXTURE FROM SAID RESERVOIR TO SAID SPRAY MEANS, THE COMBINATION COMPRISING A BRANCH LINE FROM SAID RECYCLE LINE FOR OBTAINING A SAMPLE OF SAID OIL-WATER MIXTURE, MEANS FOR SEPARATING SAID MIXTURE SAMPLE INTO OIL AND WATER COMPONENTS, A FIRST BRANCH CONDUIT FOR RECEIVING SAID SEPARATED OIL, A FIRST FLOW METER IN SAID FIRST BRANCH CONDUIT, A SECOND BRANCH CONDUIT FOR RECEIVING SAID SEPARATED WATER, A SECOND FLOW METER IN SAID SECOND BRANCH CONDUIT, MEANS FOR COMPARING THE FLOW THROUGH SAID FIRST AND SECOND FLOW METERS TO OBTAIN A SIG- 